1. Field of the Invention
The present invention relates to a printing system, printing apparatus, printing method and information processing apparatus which register character image data from an information processing apparatus such as a host computer to a printing apparatus such as a printer and reuse image data registered in the printing apparatus when the same character is to be printed.
The present invention further relates to an information processing apparatus such as a host computer for downloading fonts to a printing apparatus and a storage medium storing a font download control program which is to be executed in the information processing apparatus.
2. Related Background Art
A prior art printing system, which has a function to generate character image data in a host computer, generates character image data which comply with resolutions of a display and a printer, respectively, and transfers the generated character image data to the display and the printer to realize a so-called WYSIWYG print environment in which the same design as that displayed on the display is printed by the printer.
In such a print environment, character image date is transferred to the printer character by character. A method of storing the transferred character image data in the printer and reusing the stored character image data when the same character is to be printed is adopted in the prior art.
However, in the prior art printing system, when the character image data is transferred to the printer, the amount of data to be transferred is large and a print speed is lowered compared to a case where the characters are printed by using font information such as type of font, size and modification and character codes.
Further, when the character image data is stored in a RAM of the printer, the amount of the character image data is large and an available capacity of the RAM is small and a print processing speed is reduced.
Recently, the WYSIWYG (What You See Is What You Get) environment in which the same design as that displayed on the display is printed by the printer has been realized by providing a mechanism for generating the character image data in the host computer and generating the character image data which conform to the resolutions of the display and the printer, respectively, for the display and the printer. In such a printing environment, it is necessary to transfer the character image data to the printer. In the past, when the printing is to be made in this environment, a method for transferring the character image data character by character (character image drawing) or a method for storing the transferred character image data in the printer and reusing the stored image data when the same character is to be printed (character image downloading) has been used.
In the method for printing by the character image downloading, it is a common control method to select a group of characters having the same character attributes (font name, character size, cell size and character modification) as a character set and identifying the characters contained in the character set by the character codes. In this case, the image data of one character is represented by a combination of the character set and the character codes.
In order to control the character printing by the downloading from the host computer, data to indicate whether the character image data of the character to be printed has already been downloaded or not is required. Accordingly, the data indicating whether the characters have been downloaded or not is used for each character set. Hereinafter, a data area in which the data indicating whether the character has been downloaded or not is referred to as a registered character code control table. The data requires at least one bit to indicate whether the downloading has been made or not for each character code. Alternatively, all characters contained in the character set may be previously downloaded but in the character code set in which the character code is represented by a plurality of codes, the amount of data is huge and it is not practical. Accordingly, the above control method is required in downloading the characters in Japanese, Chinese or Korean.
The downloaded control memory required to attain the above needs at least one bit per character but if a memory having the number of bits corresponding to all character codes (for example, several thousands to ten and several thousands bit for Japanese) is prepared for each character set, a memory in the host is pressured. In actuality, when the printing by the downloading is to be conducted, the number of characters that can be registered is normally limited because of a limit in the capacity of the RAM on the printer. Accordingly, in the prior art, a maximum number of characters that can be registered is set for each character set, memories each for storing the character codes which correspond in number to the number of characters are provided and the downloaded character codes are stored therein a list form to control the downloaded character codes. Each time the character image is downloaded, the data indicating that it was downloaded is recorded in the registered character code control table, and when it happens that the downloading cannot be performed during the printing, the printing by the downloading is stopped and other printing method (for example, the image drawing) is selected or the previously downloaded data is deleted and the new data is downloaded in the emptied area.
In the prior art method, however, once the upper limit of the number of characters that can be registered is reached, the image data of the frequently used character image cannot be newly downloaded.
Further, since the downloaded character codes are controlled by the list, a long search time may be required to determine and record whether the character image has been downloaded or not even if it is the frequently used character image.
Further, when the character registration control table is prepared to store the character codes of the maximum number of characters which can be downloaded for each character set, the memory size on the host becomes large and may not be secured.
It is an object of the present invention to provide printing system, printing apparatus, printing method and information processing apparatus which reduce the amount of data to be transferred from an information processing apparatus such as a host computer to improve a printing speed and a printing processing speed.
It is other object of the present invention to provide an information processing apparatus which always permits the downloading of a frequently used character and a record medium storing a program to be executed in the information processing apparatus.
It is other object of the present invention to provide an information processing apparatus which reduces a time required to determine or record whether a frequently used character has been downloaded or not and a record medium storing a program to be executed in the information processing apparatus.
It is other object of the present invention to provide an information processing apparatus which reduces a memory size required for a registered character code control table and a record medium storing a program to be executed in the information processing apparatus.
In order to achieve the above objects, the printing system of the present invention comprises an information processing apparatus and a printing apparatus in which character image data transferred from the information processing apparatus is registered in the printing apparatus and the printing apparatus prints the same character by using the registered character image data. The information processing apparatus inclines compression means for compressing the character image data to be transferred to the printing apparatus, and the printing apparatus includes registration means for registering the compressed character image data and decompression means for decompressing the compressed character image data.
In order to achieve the above objects, the printing apparatus of the present invention for registering character image data transferred from an information processing apparatus and printing the same character by using the registered character image data comprises registration means for registering the character image data compressed by the information processing apparatus; and decompression means for decompressing the compressed character image data.
In order to achieve the above objects, the printing method of the present invention for registering character image data transferred from an information processing apparatus in a printing apparatus and printing the same character by using the registered character image data comprises the steps of compressing the character image data to be transferred to the printing apparatus by the information processing apparatus, registering the compressed character image data in the printing apparatus, and decompressing the compressed character image data.
In order to achieve the above objects, the information processing apparatus of the present invention in which character image data is transferred to a printing apparatus, the transferred character image data is registered in the printing apparatus, and the same character is printed by the printing apparatus by using the registered character image code comprises compression means for compressing the character code image, and transfer means for transferring the compressed character image data to the printing apparatus.
In order to achieve the above objects, the information processing apparatus of the present invention for downloading font of a printing apparatus comprises determination means for determining a frequency of use of the font to be printed by the printing apparatus, selection means for selecting a first control table when the determination means determines that the font to be printed is of a high frequency of use and a second control table when the determination means determines that the font to be printed is of a low frequency of use.